Fears fish farm could cause shark and pollution problems dismissed

Nicole Hasham

Awash with criticism ... the NSW government rejected claims a fish farm trial off the north coast will pollute the surrounding marine environment and attract sharks.

THE state government has rejected claims a 20-hectare fish farm trial off the state's north coast will pollute a pristine marine environment and attract sharks.

As Fairfax Media reported on Wednesday, the Department of Primary Industries wants to erect up to eight floating cages within the Port Stephens-Great Lakes Marine Park.

The cages would be anchored four kilometres from shore at Providence Bay near Hawks Nest, a popular tourist spot.

The trial, the first of its kind in NSW, would test the viability of offshore fish farming and could trigger private-sector investment in similar projects.

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But critics say the proposal will increase shark activity, disturb migrating whales and dolphins and release fish effluent and chemicals.

The aquaculture manager at Port Stephens Fisheries Institute, Ian Lyall, said only disease-free fish would be stocked in the cages and therapeutic chemical use would be limited.

''If we do have to treat them, we'll be using the least amount of chemicals that we can, and also be using chemicals that are of very low toxicity and break down very quickly,'' he told ABC Radio.

The project will farm yellowtail kingfish and mulloway, and could extend to snapper and tuna. Hormones may be used in the hatchery, but not for caged fish.

Tourism boat operators are worried that sharks will linger around the cages and affect tourism. The department will monitor sharks in the trial and erect nets around the site.

A CSIRO shark expert, Barry Bruce, said the site was near a nursery area for white sharks and shark activity was already high.

The presence of fish and fish meal could entice sharks, which ''can be conditioned to stay around that source of attraction for periods longer than they would otherwise'', Dr Bruce said.

Supporters say the project will ease pressure on wild fish stocks, help develop a sustainable aquaculture industry and create jobs.

The chief executive of the Nature Conservation Council of NSW, Pepe Clarke, said aquaculture often used small wild fish as feed, which did not reduce pressure on native fish populations.

The trial will use pellets containing wild fish meal and fish oil. But the department pointed to research showing marine ingredients were expected to play a lesser role in aquaculture feed as land animal and plant sources were developed.

Mr Lyall has previously said the project could "signal to others that may want to invest in NSW waters that there is an opportunity".

Similar fish production systems are used in South Australia and Tasmania.